Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, readOnlyHint=false, idempotentHint=false, openWorldHint=true. The description adds critical behavioral context: removing the last domain deletes the site, requires confirmDeleteSite plus sites:delete, and cleanup of a Storage-hosted site requires storage:delete and bag delegation. It also clarifies it does not sign or change DNS records. This goes well beyond the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, each dense with information. The first sentence states the operation and precondition, the second covers the destructive edge case and permissions, the third clarifies non-behaviors. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive tool with no output schema, the description covers the key decision factors: when to use, what happens on last domain, required permissions, and what it does NOT do. The parameter semantics are mostly inferable, and the edge case is explicitly handled. An agent has enough to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It explains the confirmSite and confirmDomain parameters by saying 'Confirm site and full domain exactly', and mentions confirmDeleteSite as required for last-domain deletion. It doesn't detail the site/domain parameters themselves, but their meaning is obvious from the tool name and context. The description adds meaning beyond the bare schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Detach') and resource ('a domain from an owned site'), and the title reinforces it. It distinguishes itself from siblings like sites.attach_domain and sites.delete by describing the detach operation and its consequences.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says when to use it: 'after its DNS site record no longer points to this site (or it changed owner)'. It also gives a clear exclusion: 'Does not sign or change DNS records', which helps an agent avoid using it for DNS changes. It doesn't name a specific alternative tool, but the context is clear enough.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.